JP5709130B2 - Method and apparatus for producing crystalline fine particles with excellent mixing efficiency - Google Patents

Description

  The present invention relates to a method for producing crystal fine particles and an apparatus therefor, which are excellent in mixing efficiency.

  When two or more reaction substrates are reacted, if the concentration of the reaction substrate is locally uneven, a by-product is likely to be generated. Moreover, the state where the concentration is not uniform makes the particle diameter and crystal form non-uniform when the product is precipitated as crystal fine particles in the reaction system. Therefore, in order to obtain a compound with a high yield or a crystalline compound having a uniform particle size in a simple process, it is necessary to efficiently mix the reaction substrate.

  In the mixing process (mixing step), the reaction substrate fluid is forcibly stirred by laminar flow or turbulent flow, and the molecules of the reaction substrate are further diffused. According to Fick's law, since the diffusion time is proportional to the square of the diffusion distance, the diffusion time can be shortened by shortening the diffusion distance. That is, in the mixing process, by dividing the fluid of two or more reaction substrates into minute segments by forced stirring and efficiently contacting them, the mixing speed at the molecular level can be greatly improved.

  In recent years, microreactors have attracted attention as a means for increasing the mixing speed. A microreactor is a chemical reaction apparatus that utilizes a micro space of several μm to several hundred μm. By utilizing the minute space, the surface area of the reaction substrate per unit volume of the reaction system is increased, and the contact area between the reaction substrates is increased, so that efficient mixing and interfacial reaction can be performed. In addition, the normal plant that is not a microreactor greatly changes the stirring efficiency due to scale-up, so it was necessary to reexamine the reaction conditions at the time of scale-up. Since the production scale can be expanded by (increase in the number of reaction base points), a rapid transition from R & D to industrial production can be achieved. However, in reality, there is a limit to the expansion of the production scale by increasing the numbering of the microreactors, and new apparatuses and methods have been demanded.

  A membrane reactor that supplies liquid b to liquid a through a porous membrane and reacts them is expected to be an effective device for expanding the production scale while maintaining excellent mixing performance. A membrane reactor using a porous membrane made of cylindrical shirasu porous glass (Shiras porous glass, hereinafter also referred to as “SPG membrane”) is known (Non-patent Document 1). In this membrane reactor, the liquid a flows into the cylindrical porous membrane so that the streamline is a straight line parallel to the longitudinal direction of the cylindrical body, and the liquid b is supplied to the liquid a through the porous membrane. That is, since the liquid a flows so as to be orthogonal to the liquid b, it is also called a cross flow liquid. The cross flow liquid is easily removed from the film surface by the flow of the liquid b. As a result, the liquid b stays in the vicinity of the film surface, and the mixing efficiency with the crossflow liquid decreases.

  Therefore, Yong Wu et al. Proposed to arrange various types of stationary stirrers inside the cylindrical body of the cylindrical porous membrane to effectively mix the crossflow liquid in order to increase mixing efficiency. (Non-Patent Document 2). However, in this method, it is difficult to precisely control the flow of the crossflow liquid in the boundary layer on the film surface, and a sufficient mixing effect cannot be obtained.

Journal of Membrane Science, vol. 299 (2007), 190-199 Journal of Membrane Science, vol. 328 (2009), 219-227

  In view of such circumstances, it is an object of the present invention to provide a method for producing crystalline fine particles and an apparatus thereof that are excellent in mixing efficiency.

As a result of intensive studies, the inventors have supplied the liquid b containing the reaction substrate B to the swirling flow of the liquid a containing the reaction substrate A through the porous membrane, and reacting the reaction substrates A and B with each other. It has been found that the above problems can be solved. That is, the present invention
(1) A swirl flow generating step of flowing a swirl flow of the liquid a containing the reaction substrate A into a cylindrical body in which a part or all of the circumferential surface is composed of a porous film, and the porous film through the porous film Production of crystal fine particles, including a reaction step in which liquid b containing reaction substrate B capable of reacting with reaction substrate A is supplied to the swirl flow and mixed, and reaction substrates A and B are reacted to precipitate crystal fine particles. Method,
(2) A part or the whole of the circumferential surface is a cylindrical body composed of a porous membrane, and the inlet of the liquid a containing the reaction substrate A on the circumferential surface near one end and the other end A cylindrical body having a product outlet in a cross section, connected to the inflow port so that the liquid a can flow in substantially perpendicular to the axis of the cylindrical body and from the tangential direction of the inner wall surface, with respect to the axis of the cylindrical body And an inlet tube extending substantially vertically and extending in the tangential direction of the cylindrical body, a reservoir for storing the liquid b containing the reaction substrate B provided outside the circumferential surface of the cylindrical body, and the liquid from the reservoir a method of (1) using an apparatus comprising supply means for supplying b into the cylindrical body;
By providing the above, the above-mentioned problem is solved.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for producing crystal fine particles and an apparatus thereof that are excellent in mixing efficiency. In particular, low polydispersity crystal particles can be produced by the present invention.

It is a conceptual diagram of the preferable apparatus of this invention. It is a conceptual diagram of the other preferable apparatus of this invention. It is sectional drawing which looked at the YY cross section in FIG. 1 from the direction of the arrow. It is a 1000 times SEM image of the calcium carbonate microparticles | fine-particles obtained in the Example. It is a 20000 times SEM image of the calcium carbonate microparticles | fine-particles obtained in the Example. It is a 1000 times SEM image of the calcium carbonate microparticles | fine-particles obtained by the comparative example. It is a 7500 times SEM image of the calcium carbonate microparticles | fine-particles obtained by the comparative example.

1. Manufacturing Method The manufacturing method of the present invention includes a swirling flow generating step in which a swirling flow of a liquid a containing a reaction substrate A is flown into a cylindrical body in which a part or all of a circumferential surface is formed of a porous film, and the porous A reaction step in which a liquid b containing a reaction substrate B capable of reacting with the reaction substrate A is supplied to the swirl flow through the membrane, and the reaction substrates A and B are reacted to precipitate crystal particles; Including.

(1) Swirl flow generation step 1) Liquid a containing reaction substrate A
In this step, the liquid a containing the reaction substrate A is caused to flow into a cylindrical body in which a part or all of the circumferential surface is formed of a porous film. The reaction substrate A is a substance that reacts with the reaction substrate B supplied in the next step. The reaction substrate A may be either an inorganic substance or an organic substance. Examples of inorganic substances include, but are not limited to, inorganic acids such as hydrochloric acid, inorganic bases such as sodium hydroxide, carbonates such as sodium carbonate, inorganic acids, inorganic bases, inorganic reducing agents, inorganic oxidizing agents, hydrochlorides, Carbonates, nitrates, sulfates, carbonates and the like are included. Examples of organic substances include, but are not limited to, organic acids such as acetic acid, organic bases such as amines, organic salts thereof, esters such as ethyl acetate, alcohols such as ethyl alcohol, various coupling reagents and platinum (II). Various complex compounds such as acetylacetonate are included. As the reaction substrate A, one type of substrate may be used alone, or a plurality of types of substrates may be used in combination.

  Liquid a can be prepared by dissolving or dispersing reaction substrate A in a known solvent. The solvent may be aqueous or oily. Further, when the reaction substrate A is a liquid, the liquid a may be used as it is. The liquid a may be a liquid when it is supplied to the cylindrical body. Therefore, for example, a substance that is solid at room temperature but becomes liquid when heated can also be used as the liquid a. Alternatively, a liquid in a supercooled state that is liquid at room temperature but solidifies with time can also be used. In consideration of workability, this step is preferably performed at room temperature (20 to 30 ° C.). Therefore, the liquid a is preferably liquid at room temperature.

2) Cylindrical body A cylindrical body refers to a cylindrical member having a hollow inside. In the cylindrical body of the present invention, a part or all of the circumferential surface is constituted by a porous film. The porous membrane refers to a membrane having a large number of minute through holes. As such a film, a known porous film made of glass, ceramic, nickel or the like may be used. In the present invention, a glass porous film is preferable, and a porous film (SPG film) made of shirasu porous glass described in Non-Patent Document 1 is more preferable. The average pore size of the porous membrane is not limited as long as it is generally within the range of the pore size of the porous membrane, but in order to obtain an industrially suitable particle size when the compound is obtained as crystalline fine particles, 0.5% 10 μm is preferable, and 1 to 5 μm is more preferable. The porosity and average pore diameter of the porous membrane can be measured by a mercury intrusion method (using an automatic porosimeter).

  That part or all of the circumferential surface is composed of a porous membrane means that the portion used to supply the liquid b on the circumferential surface is composed of a porous membrane, and other portions are made of other materials. It means that it may be configured. However, in the present invention, in order to increase the membrane area (hereinafter also referred to as “effective membrane area”) that can be effectively used for the production of the compound, it is preferable that the entire circumferential surface is composed of a porous membrane.

  As will be described later, in the present invention, the liquid a is preferably introduced from the circumferential surface of the cylindrical body substantially perpendicularly to the axis of the cylindrical body. In such a case, it is preferable that the entire circumferential surface of the cylindrical body is formed of a porous film, and the porous film in the vicinity where the liquid a is introduced is treated so that the liquid a does not leak out of the cylindrical body. . Specifically, the liquid a can be prevented from leaking out of the cylindrical body by coating the inner wall surface or the outer wall of the portion of the porous membrane. Alternatively, a cylindrical body whose circumferential surface is made of another material is connected to the end of the cylindrical body whose circumferential surface is made of a porous film to form an integral cylindrical body, which is used as the cylindrical body of the present invention. May be.

  The shape and dimensions of the cylindrical body of the present invention are not particularly limited, but the cross-sectional area is preferably constant in the length direction and the inner diameter is preferably 5 to 100 mm. If the inner diameter is less than 5 mm, it may be difficult to generate a swirling flow in the cylinder. If the inner diameter exceeds 100 mm, the supply amount of the liquid a required to generate the swirling flow becomes excessive. There is. The length of the cylindrical body is preferably 2 to 50 times the inner diameter. When the length of the cylinder is less than twice the inner diameter, the effective membrane area becomes small, so that the mixing efficiency can be lowered. On the other hand, if the length of the cylinder exceeds 50 times the inner diameter, the turning speed in the cylinder becomes non-uniform, and the mixing efficiency may be reduced.

3) Swirl Flow A swirl flow is a flow having a flow along the axis of a cylindrical body and a flow along a circumferential surface. The swirling flow can be generated by a known method. For example, it is possible to provide a screw at one end of the cylindrical body, supply the liquid a to the cylindrical body while rotating the screw, and allow the swirling flow of the liquid a to flow in the cylinder. However, in the present invention, it is preferable to flow a swirl flow as shown in FIG. When the swirl flow is generated in this way, there is an advantage that the swirl speed is easily controlled. Hereinafter, this aspect will be described with reference to the drawings.

  FIG. 1 shows an overview of a preferred apparatus of the present invention. In FIG. 1, 1 is a manufacturing apparatus of the present invention, and 10 is a cylindrical body. In the cylindrical body 10, reference numeral 100 denotes a porous membrane portion whose circumferential surface is constituted by a porous membrane, and 101 is a non-porous membrane portion whose circumferential surface is constituted by another member. 12 is an inlet for liquid a, 14 is a discharge port, 20 is an introduction pipe, 22 is a member constituting the introduction pipe, 30 is a discharge pipe, 32 is a member constituting the discharge pipe, 40 is a reservoir for liquid b, 42 Is an introduction pipe for the liquid b, and 44 is a member constituting the reservoir. In FIG. 1, 80 is a seal ring. 3 is a cross-sectional view of the YY cross section in FIG. 1 viewed from the direction of the arrow. In FIG. 3, reference numeral 16 denotes an inner wall surface of the cylindrical body 10.

  As shown in FIG. 1, an inflow port 12 is provided on a circumferential surface near one end of the cylindrical body 10 (that is, the circumferential surface of the non-porous membrane portion 101). An introduction pipe 20 extending substantially perpendicular to the axis is connected. The vicinity here refers to a range from the origin to 0.1 when the end of the cylinder is the origin and the total length of the cylinder is 1. The term “substantially vertical” means that the angle formed by the axis of the introduction tube 20 and the axis of the cylindrical body 10 is 85 to 95 °, preferably 88 to 92 °, more preferably 90 ° (vertical). As shown in FIG. 3, the introduction pipe 20 extends in the tangential direction of the cylindrical body 10, and can introduce the liquid a from the tangential direction of the inner wall surface 16 of the cylindrical body 10. That is, a part of the inner wall surface of the introduction pipe 20 is flush with the tangent line of the inner wall surface 16 of the cylindrical body 10. Since the flow of the liquid a flows along the circumferential direction on the inner wall surface 16, it is pushed out toward the other end of the cylindrical body 10, thereby generating a swirling flow. That is, in this preferred embodiment of the present invention, the point that the liquid a flows in from the direction perpendicular to the axis of the cylindrical body 10 along the circumferential surface of the cylindrical body 10 to obtain a swirling flow is remarkably different from the conventional cross flow system. Different.

  In the present invention, the speed in the circumferential direction of the swirling flow (hereinafter also referred to as “swirling speed”) and the speed in the axial direction of the cylindrical body (hereinafter also referred to as “axial speed”). Is preferably controlled by a value obtained by dividing the flow rate of the liquid a flowing through the introduction pipe 20 by the inner cross-sectional area of the introduction pipe 20, that is, the inflow linear velocity. The inflow linear velocity should be optimized in relation to the inner diameter of the cylindrical body, but is preferably about 1 to 40 m / s, more preferably 2 to 20 m / s. When the inflow linear velocity is within this range, the mixing efficiency is improved. Moreover, crystal fine particles having a low polydispersity can be obtained. The cross section of the introduction tube 20 may be an arbitrary shape such as a square or a circle, but a circle is preferable because it is easy to manufacture and makes the flow of the liquid a in the introduction tube 20 uniform.

  Further, in the present invention, it is preferable that the thickness of the introduction tube 20 and the thickness of the cylindrical body 10 have a certain relationship, because a swirling flow can be efficiently generated in the cylindrical body 10. The relationship between the thickness of the cylindrical body 10 and the introduction pipe 20 is that the area ratio S1 / S2 is 4 to 64, where S1 is the inner diameter sectional area of the cylinder 10 and S2 is the inner diameter sectional area of the introduction pipe 20. preferable. For example, in the cylindrical body 10, the inner diameter cross-sectional area means a cross-sectional area of a portion through which the liquid a flows, and specifically, is an area of a circle having an inner diameter as a diameter. In particular, when the inner diameter of the cylindrical body 10 is a circle having X1 and the cross section of the introduction pipe 20 is an inner diameter X2, the inner diameter ratio X1 / X2 is preferably 2-8.

  Furthermore, the mode and axial velocity of the swirling flow in the cylindrical body 10 are influenced by the size of the discharge port 14 (Non-patent Document 3: Journal of the Japan Society of Mechanical Engineers, Vol. 58, No. 58, pages 1668 to 1673 (1992)). . When the cylindrical body 10 of the present invention has the discharge port 14 as shown in FIG. 1, it is preferable that the cross section of the discharge port 14 is circular from the viewpoint of easy manufacture. When the inner diameter of the circular outlet 14 is X0, the ratio X1 / X0 between the inner diameter X1 of the cylindrical body 10 and the inner diameter X0 of the outlet 14 is preferably 1 to 5, and more preferably 1 to 3. X0 can be adjusted by the shape of the member 32 disposed at the end of the cylindrical body 10. The member 32 will be described later.

  In this manufacturing method, the direction in which the apparatus of the present invention is installed is not limited, but it is preferable to install the apparatus so that the axis of the cylindrical body 10 is substantially vertical. This is because the swirling motion is less affected by the gravitational acceleration when the swirling surface of the liquid a swirling inside the cylindrical body 10 is orthogonal to the direction of gravity. The term “substantially vertical” means that the angle between the horizontal line and the axis of the cylindrical body 10 is 85 to 95 °, preferably 88 to 92 °, more preferably 90 °.

By using the swirling flow of the liquid a generated in this way, high mixing efficiency can be obtained and crystal particles with low polydispersity can be obtained. This mechanism will be described in detail later.
Both liquids are vigorously stirred by the swirling flow. Therefore, the greater the energy that the liquid a has, the higher the stirring efficiency. Accordingly, the flow rate of the liquid a is preferably larger than the flow rate of the liquid b described later. Specifically, the ratio of the two (flow rate of liquid a / flow rate of liquid b) is preferably 4 to 10.

  Further, the reaction substrate B contained in the liquid b may be less mobile in the reaction system than the reaction substrate A contained in the liquid a. This is because the diameter of the liquid column of the liquid b ejected from the porous membrane is considered to be about the same as the pore size of the porous membrane (usually about 2 μm), so that the diffusion distance for colliding with the reaction substrate A can be short. . In order for the reaction substrate A having high mobility to collide with the substrate B, it is necessary to move in the liquid a for a long distance. However, the reaction substrate B efficiently collides with the large mobility of the substrate A and vigorous stirring of the liquid a. can do. As a result, crystal fine particles having a smaller particle diameter are obtained.

On the other hand, if the mobility of the reaction substrate A contained in the liquid a is inferior to that of the reaction substrate B, the liquid a hardly increases the mobility of the reaction substrate A, and thus the particle diameter of the obtained crystal fine particles tends to be large. The mobility of the reaction substrate in the reaction system depends on the bulkiness including the solvation structure. For example, the mobility of carbonate ions is 7.2 × 10 ⁻⁴ (cm ² s ⁻¹ V ⁻¹ ), and the mobility of calcium ions is 6.2 × 10 ⁻⁴ (cm ² s ⁻¹ V ⁻¹ ). .

The ion mobility can be obtained by the following equation.
u _i = λ _i / F
Here, u _i is the mobility of ion i (cm ² s ⁻¹ V ⁻¹ ), λ _i is the equivalent ionic conductivity (Ω ⁻¹ cm ² mol ⁻¹ ), and F is the Faraday constant.

(2) Reaction step 1) Liquid b containing reaction substrate B
In this step, the liquid b is supplied to the swirl flow through the porous membrane. Liquid b contains reaction substrate B. The reaction substrate B may be any material that reacts with the reaction substrate A to produce crystals that precipitate in the reaction system, and specific examples include those exemplified for the reaction substrate A. Similar to the reaction substrate A, the reaction substrate B may be one or more substances. The liquid b can be prepared in the same manner as the liquid a. However, it is preferable that the solvents of the liquid a and the liquid b are compatible with each other because the reaction substrate B diffuses faster and the mixing efficiency can be further increased.

  As a preferable combination of the liquids a and b, a combination in which the liquid a is a sodium carbonate aqueous solution and the liquid b is a calcium chloride aqueous solution can be exemplified. In this case, calcium carbonate can be produced as crystal fine particles.

2) Supply method The liquid b is supplied into the swirling flow of the liquid a through the porous membrane. The supply method is not particularly limited. However, as shown in FIG. 1, in order to adjust the pressure appropriately by arranging the member 44 around the outer periphery of the cylindrical body 10 to provide the reservoir 40 and filling the reservoir 40 with the liquid b. It is preferable to supply using a pressure control device (not shown). Since the swirling flow of the liquid a is generated inside the cylindrical body 10, the liquid b is quickly mixed with the liquid a when supplied into the cylindrical body 10. In this invention, it is preferable to make the supply rate in this case into about 50-250 mL / min. In the method described in Non-Patent Document 1, the supply rate is much lower than 50 to 250 mL / min, and the mixing efficiency decreases when the supply rate is increased. However, according to the present invention, high mixing efficiency can be obtained even if the supply speed is increased. It is considered that the liquid b supplied at this speed is jetted from the porous film and supplied into the swirling flow of the liquid a. Although the temperature which supplies the liquid b is not specifically limited, As above-mentioned, room temperature (20-30 degreeC) is preferable.

(3) Extraction Step The manufactured compound is extracted from the discharge port 14 provided at one end of the cylindrical body 10. As described above, the discharge port is preferably provided in a circular shape having a constant inner diameter in the cross section of one end of the cylindrical body 10. Further, the compound may be removed through a discharge pipe 30 connected to the discharge port 14.

(4) Mechanism of action According to the present invention, the mechanism by which high mixing efficiency is obtained and crystal fine particles having a low polydispersity are obtained is not limited, but is considered as follows. First, the liquid b supplied through the porous film forms minute segments in the swirling flow of the liquid a. This shape is a droplet or a liquid column. The liquid column is a columnar flow composed of the liquid b, and its cross section is usually circular. Further, in the present invention, the liquid column includes those deformed into a distorted shape (such as a wavy shape) by a swirling flow.

  When the liquid a is flowed as a cross flow flow as in the conventional case, the cross flow is pushed away from the surface of the porous membrane by the flow of the segment of the liquid b. Therefore, the liquid b tends to stay near the porous membrane surface. When the liquid b is supplied as a jet, this phenomenon becomes more prominent because the liquid a is more easily moved away from the film surface. When the liquid b stays in this way, the mixing efficiency is lowered, and the particle diameters of the generated crystal particles vary.

  On the other hand, in the present invention, the liquid a is allowed to flow as a swirl flow. Since the swirling flow has a centrifugal acceleration according to the swirling speed, it is not separated from the porous membrane surface by the flow of the segment of the liquid b. Therefore, the liquid b is quickly dispersed as fine segments in the swirling flow without staying. Since the porous film has innumerable pores having a uniform pore diameter, a large number of fine segments of the liquid b having the same size are formed. Since the reaction substrate B diffuses from the fine segment and reacts with the reaction substrate A, a large number of reaction base points are formed at the same time. For this reason, in the present invention, the mixing efficiency is increased, and the reaction substrates A and B react quickly to obtain crystal particles having a low polydispersity. Furthermore, in the method of the present invention, since a large number of reaction base points can be formed, the production volume can be scaled up without increasing the size of the apparatus. At this time, if the compatibility of the solvent of the liquid a and the solvent of the liquid b is high, the dispersibility of the minute segment of the liquid b and the diffusibility of the reaction substrate B in the liquid b are increased, so that the reaction proceeds more rapidly. .

  Thus, the present invention can mix the liquid a and the liquid b with extremely high efficiency. Therefore, the present invention is particularly effective in diffusion-controlled reactions, that is, reactions in which improvement of mixing efficiency is a key.

(5) Others In the above description, the case where the liquid a and the liquid b include the reaction substrates A and B that react with each other has been described. However, the present invention uses the liquid b in which the substance B is dissolved in the solvent b ′ and the liquid a in which the substance B is not dissolved but the solvent b ′ is dissolved to precipitate the substance B in the product mixture. Fine particles of substance B can also be produced. For example, when the liquid b is a polymer solution containing a polymer and its good solvent (such as THF), and the liquid a is a poor solvent (such as methanol) of the polymer, low-dispersion polymer particles can be produced.

2. Crystal Fine Particles Crystal fine particles obtained by the production method of the present invention can be isolated from the product mixture by a known method to obtain a final product. For example, examples of isolation methods include filtration. The average particle size defined by the particle size (d ₅₀ ) of the crystal fine particles produced according to the present invention is 50% or less, more preferably 50 μm or less. It is preferably 30 μm or less, particularly preferably 5 μm or less. The lower limit of d ₅₀ is preferably 0.01 μm or more, more preferably 0.1 μm or more, and further preferably 0.5 μm or more. Further, the polydispersity (hereinafter also referred to as “span”) defined by the following formula (1) is preferably 1.5 or less, and more preferably 1.0 or less. The lower limit of the span is not limited, but is preferably 0.5 or more.

Span = (d ₉₀ −d ₁₀ ) / d ₅₀ (1)
d ₁₀ : Particle diameter in 10% cumulative particle distribution d ₉₀ : Particle diameter in 90% cumulative particle distribution d ₅₀ : Particle diameter in 50% cumulative particle distribution In the present invention, for example, calcium carbonate fine particles can be produced. Calcium carbonate is an inexpensive, non-toxic, opaque white fine powder, and is used as a filler for paper or plastic, an opacifying agent, and the like. Since the effect of addition varies depending on the particle diameter and shape of the calcium carbonate crystal, fine particles with low polydispersity are required. According to the present invention, such calcium carbonate fine particles can be efficiently produced.

  In addition, nano-sized fine crystal particles (for example, nano-sized pigments) having an average particle diameter of about 50 to 100 nm can be produced according to the present invention. The particle diameter can be controlled mainly by the speed of the swirling flow, and the particle diameter of the fine particles obtained becomes smaller as the swirling flow speed becomes higher. In particular, in order to obtain nano-level crystal fine particles, the flow rate of the liquid a is preferably 2000 mL / min or more, that is, the swirl speed is 15000 rpm or more.

3. Apparatus The manufacturing method of the present invention is (1) a cylindrical body in which a part or all of the circumferential surface is formed of a porous film, and the liquid a inlet and the other are provided on the circumferential surface near one end. A cylindrical body having a product outlet on one end cross section; (2) connected to the inlet so that the liquid a can flow in substantially perpendicular to the axis of the cylindrical body and from the tangential direction of the inner wall surface; An introduction pipe extending substantially perpendicular to the axis of the cylindrical body and extending in a tangential direction of the cylindrical body; (3) a liquid b storage portion for storing the liquid b provided outside the circumferential surface of the cylindrical body (4) and a supply means for supplying the liquid b from the liquid b reservoir into the cylindrical body. Hereinafter, it demonstrates, referring FIG. 1 which shows a preferable example of this apparatus.

(1) Cylindrical body The cylindrical body 10 functions as a reactor. The material, shape, dimensions, etc. constituting the cylindrical body are as described above.

(2) Introducing pipe The introducing pipe 20 has a function of generating a swirling flow. As already described, the introduction pipe 20 is connected to the inlet 12 provided on the circumferential surface of the cylindrical body 10, and extends substantially perpendicular to the axis of the cylindrical body and in the tangential direction of the cylindrical body. The speed of the swirling flow can be adjusted by adjusting the thickness of the introduction pipe 20. The introduction pipe 20 is preferably formed as shown in FIGS. That is, a thick cylindrical member 22 having an inner diameter substantially the same as the inner diameter of the cylindrical body 10 and having one end closed is prepared and disposed so as to cap the end of the cylindrical body 10. Next, the member 22 is provided with a through-hole that is perpendicular to the axis of the cylinder 10 and extends in the tangential direction of the cylindrical body 10. The liquid a flows through the introduction tube 20 and the circumferential surface formed by the member 22 flows along the inner wall of the non-porous membrane portion 101 made of a material other than the porous membrane, and efficiently generates a swirling flow. it can. Further, the turning speed can be easily adjusted by the size of the through hole. The material of the member 22 is not particularly limited, but stainless steel is preferable in consideration of resistance to acids, alkalis, and organic solvents.

  In addition, as shown in FIG. 2, an introduction tube 20 may be provided in the porous portion 100 of the cylindrical body 10. However, in this case, it is preferable that the region near the introduction pipe 20 of the porous portion 100 is subjected to a coating process so that the liquid a does not leak.

(3) Liquid b storage part It is preferable to arrange the member 44 so as to cover the outer periphery of the cylindrical body 10, and use the space formed between the inner wall of the member 44 and the outer wall of the cylindrical body 10 as the storage part 40. Since the storage part 40 can supply the liquid b from the whole porous membrane part 100 of the cylindrical body 10, production efficiency improves. In this case, the gap interval, that is, the difference between the inner radius of the member 44 and the outer radius of the cylindrical body 10 is preferably 1.0 to 10 mm, and more preferably 1.5 to 4.0 mm. In the case where the gap is narrower than 1.0 mm, if the supply speed of the liquid b is increased, pressure distribution is generated in the reservoir 40, and the uniformity of the speed of the liquid b passing through the porous membrane pores may be impaired. There is. On the other hand, if this gap is larger than necessary, the amount of liquid b stored increases, and the amount of liquid b discarded during disassembly and cleaning of the apparatus increases, resulting in waste of resources.

  The material of the member 44 is not particularly limited, but stainless steel is preferable in consideration of resistance to acids, alkalis, and organic solvents. Further, a seal ring for preventing liquid from leaking out of the apparatus may be disposed at a site where the cylindrical body 10, the member 44, and the member 22 are connected. Examples of seal rings include known O-rings.

(4) Supply means The supply means is not particularly limited, but a pump that generates less pulsating flow is preferable. The supply means is connected to the liquid b introducing pipe 42 provided in the member 44.

(5) Discharge port and discharge pipe The apparatus of the present invention preferably has a discharge port 14 and a discharge pipe 30 at the other end of the cylindrical body 10. The shape and dimensions of the discharge port 14 are as described above. A discharge pipe 30 connected to the discharge port 14 is formed by preparing a cylindrical member 32 having a desired inner diameter and having a through-hole for discharge and arranging the end of the cylindrical body 10 to be capped. It is preferable to do. The material of the member 32 is not particularly limited, but stainless steel is preferable in consideration of resistance to acids, alkalis, and organic solvents.

[Production Example 1] Preparation of the device A cylindrical body having an outer diameter of 10 mm, an inner diameter of 9 mm, and a length of 150 mm, which is composed of a porous film (SPG film) made of Shirasu porous glass having an average pore diameter of 2.1 μm on the entire circumferential surface (SPG Techno Co., Ltd., SPG film, lot number PJN08J14) was prepared. A cylindrical member 22 made of stainless steel having a thickness larger than that of the SPG film cylinder and having the same inner diameter as that of the SPG film cylinder and having one end closed was prepared. As shown in FIG. 1, this member 22 is arranged so as to cap the end of the SPG membrane cylinder, and the end of the SPG membrane cylinder has a cylindrical shape with a circumferential surface made of stainless steel and having a length of 5 mm. A cylindrical body 10 having a porous portion 100 and a non-porous 101 and having a total length of 155 mm was prepared. The member 22 is provided with a through-hole that is perpendicular to the axis of the cylindrical body 10 and extends in the tangential direction of the cylindrical body 10. The cross section of the introduction tube was a circle and the inner diameter was 2.0 mm.

  The member 44 was disposed so as to cover the outer peripheral portion of the cylindrical body 10 to form the storage portion 40. The height of the reservoir 40 (the difference between the inner radius of the member 44 and the outer radius of the cylindrical body 10) was 2.0 mm. A cylindrical member 32 made of stainless steel having a discharge port having an inner diameter of 4.5 mm is arranged at the other end of the cylindrical body 10 so as to cap the end of the cylindrical body 10, and the discharge port 14 and the discharge pipe 30 are arranged. Formed. As shown in FIG. 1, O-rings were inserted into both ends of the member 44 in the space between the member 44 and the cylindrical body 10. In this way, the manufacturing apparatus of the present invention was prepared. As shown in FIG. 1, this manufacturing apparatus was installed so that the axis of the cylindrical body was substantially vertical and the introduction tube 20 was positioned below.

[Reference Example 1] Evaluation of mixing efficiency The mixing efficiency of the present invention was evaluated by the Villermuux-Dushman method. This method is a method for evaluating mixing efficiency by a competitive complex reaction consisting of the following reactions (1), (2) and (3). When the oxidation-reduction reaction (2) with the neutralization reaction (1) is carried out competitively, the neutralization reaction of the reaction (1) proceeds locally under insufficient mixing, resulting in local residual hydrogen ions. As a result, reaction (2) is biased to the right and iodine molecules (I ₂ ) are generated. Since this iodine molecule exists in equilibrium with triiodide ions as shown in reaction (3), the mixing efficiency can be evaluated by quantifying the generated triiodide ions. That is, when the amount of triiodide ions is large, it can be evaluated that the mixing efficiency is low.

  A liquid mixture of equal amounts of boric acid and sodium hydroxide containing potassium iodide and potassium iodate (referred to as “boric acid buffer solution”) was prepared as the liquid a, and each time from the introduction pipe 20 of the apparatus manufactured in Example 1, Introduced at a flow rate of 0.5, 1.0, 1.5, 2.0, and 2.5 L / min, a swirling flow was generated in the internal space of the cylindrical body 10 (Experiments I-1 to I-5 and Experiments). II-1 to II-5). On the other hand, moderately diluted sulfuric acid as liquid b was ejected into a boric acid buffer solution swirling through a porous membrane. The flow rate ratio (mixing ratio) of the borate buffer and dilute sulfuric acid solution was 10: 1 and 4: 1. Each of the above experiments was repeated three times.

  In this example, the concentration of the reaction solution used in this example was as shown in Table 1, and the pH of the solution after mixing was adjusted to 8.5 to 9.5 so that the generated triiodide ions were stable. . Triiodide ions were quantified at an absorption wavelength of 353 nm. When the absorbance was 1.7 or more, the reaction system was diluted with distilled water, the absorbance was measured, and the absorbance was obtained by multiplying by the dilution factor. The results are shown in Table 2.

[Reference Example 2]
In the apparatus manufactured in Manufacturing Example 1, the end of the cylindrical body 10 on the introduction tube 20 side was an open end, and a manufacturing apparatus for comparison was prepared. The experiment was carried out in the same manner as in Reference Example 1 except that a borate buffer solution was flowed from the open end in the longitudinal direction of the cylindrical body 10, and triiodide ions were quantified (Experiments I-6 to I-10 and Experiments). II-6 to II-10). The results are shown in Table 2.

  From the results in Table 2, it is clear that the amount of triiodide ions quantified in Reference Example 1 is smaller than the amount of triiodide ions quantified in Reference Example 2. From this result, it is clear that the present invention has high mixing efficiency.

[Reference Example 3] Influence of Porous Membrane Pore Diameter on Mixing Efficiency The flow rate of liquid a was 0.5 L, 1.0 L, 1.5 L, 2.0 L, and 2.5 L per minute, and the average pore diameter of the porous membrane was The mixing efficiency was evaluated in the same manner as in Reference Example 1 as 1.1 μm, 2.1 μm, 4.9 μm, and 10.1 μm (experiment numbers III to VI). The flow rate ratio between liquid a and liquid b was all 10: 1. The concentrations of the reagents used in this example are shown in Table 3. Table 4 shows the absorbance of triiodide ions obtained in each experiment.

From Table 4, it is clear that almost the same mixing efficiency can be obtained using any porous membrane having an average pore diameter of 1.1 to 10.1 μm.
Example 1 Production of Calcium Carbonate A 0.15M sodium carbonate solution as a liquid a and a 1.5M calcium chloride solution as a liquid b were prepared. The average pore diameter of the porous membrane (SPG membrane) was 2.1 μm.

  From the introduction pipe 20 of the apparatus manufactured in Reference Example 1, the liquid a is flowed at a flow rate of 0.5 L, 1.0 L, and 1.5 L per minute, and the liquid b is 0.05 L, 0.1 L,. It was supplied into the cylindrical body 10 through the porous membrane at a flow rate of 15 L. As a result, a calcium carbonate suspension was obtained. The suspension was irradiated with ultrasonic waves for 12 minutes to remove and agglomerate fine particles and dispersed, and then the particle size distribution of the suspended particles was measured by a laser diffraction particle size distribution measuring device (device name wing-SALD 200, Inc.). (Manufactured by Shimadzu Corporation). Further, the suspension was dried to isolate calcium carbonate fine particles, gold was deposited, and observed with a scanning electron microscope (SEM) (device name: JSM-5310, manufactured by JEOL Ltd.) (FIG. 4). And FIG. 5). Production conditions and results are shown in Table 5.

[Comparative Example 1] Production of calcium carbonate Calcium carbonate was produced and evaluated in the same manner as in Example 1 except that the liquid a was in a linear flow as in Reference Example 2. The results are shown in Table 5.

In Example 1, the average particle diameter of calcium carbonate obtained when the flow rate of the swirling flow was 0.5 L, 1.0 L, and 1.5 L per minute was 1.5 μm, 1.2 μm, and 0.8 μm. . Therefore, it was clarified that calcium carbonate fine particles can be obtained by the present invention, and that the particle diameter generated can be controlled by the flow velocity of the swirling flow. Moreover, the particle size distribution span (D ₉₀ -D ₁₀ ) / D ₅₀ of the obtained fine particles is 1.1 to 1.3 and the polydispersity is low, and the span is hardly affected by the swirling flow velocity. It became clear. The SEM images of the calcium carbonate fine particles prepared in Experiment No. 3 of Example 1 are shown in FIGS.

  In Comparative Example 1, the average particle diameter of calcium carbonate obtained when the flow rate of the linear flow was 0.5 L, 1.0 L, and 1.5 L per minute was 9.4 μm, 8.0 μm, and 5.8 μm. It was revealed that the particle size was larger than the calcium carbonate obtained in Example 1. From the comparison between Example 1 and Comparative Example 1, it was revealed that the calcium carbonate particle size can be refined to 1/6 to 1/7 in terms of particle diameter and about 1/300 in terms of particle volume in the swirling flow method. SEM images of the calcium carbonate fine particles prepared in Experiment No. 6 of Comparative Example 1 are shown in FIGS.

[Example 2] Production of calcium carbonate In order to examine the influence of the reaction substrate concentration, the concentration of liquid a was 0.06, 0.09, 0.12, 0.15 mol / L, and the concentration of liquid b was 0.00. Calcium carbonate fine particles were produced in the same manner as in Example 1 except that the concentration was 6, 0.9, 1.2, and 1.5 mol / L. The production conditions and results are shown in Table 6.

  From the results of Table 6, it can be seen that when the concentration of both the liquid a and the liquid b is high, crystal fine particles having a smaller average particle diameter can be obtained. That is, it can be seen that a shorter moving distance for the collision between carbonate ions and calcium ions is more effective in obtaining crystal fine particles having a smaller average particle diameter.

Example 3 Production of Calcium Carbonate To study the effect of the flow ratio of liquid a and liquid b, the flow ratios were 6: 1, 8: 1 and 10: 1 and stoichiometrically with respect to calcium carbonate production. Calcium carbonate fine particles were produced in the same manner as in Example 2 except that the concentration was adjusted so that the reaction proceeded without excess or deficiency. Production conditions and results are shown in Table 7.

  From the results in Table 7, it can be seen that when the flow rate ratio a: b is 8: 1 or 10: 1 rather than 6: 1, crystal fine particles having a smaller average particle diameter can be obtained. Conversely, the span was smaller when the flow ratio of both liquids was 6: 1. This indicates that the smaller the degree by which the kinetic energy of the swirling flow is attenuated by the membrane permeate is more effective for preparing fine crystals.

[Example 4] Production of calcium carbonate The effect of exchanging the reaction substrate supplied as the swirl flow and the reaction substrate supplied as the membrane permeation flow in Example 3 was examined. That is, in Example 3, the liquid a was a 0.15 mol / L Na ₂ CO ₃ aqueous solution, and the liquid b (membrane permeate) was a 1.5 mol / L CaCl ₂ aqueous solution. The 15 mol / L CaCl ₂ aqueous solution and the liquid b were 1.5 mol / L Na ₂ CO ₃ aqueous solution. The flow ratio of liquid a and liquid b and the flow rates of both liquids were the same as in Example 3. The production conditions and results are shown in Table 8.

  Comparing the results of Example 3 and Example 4, it was found that the size and span of the microcrystalline particles produced by changing the reaction substrate of the swirling flow and the membrane permeate differed greatly. This is considered to be due to the difference in the mobility of calcium ions and carbonate ions in water. In other words, if the calcium ion, which has a lower mobility than the bicarbonate ion, is included in the membrane permeation flow that requires a shorter diffusion distance to collide with the bicarbonate ion, crystal particles with a smaller particle diameter can be obtained. You can see that

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of this invention 10 Cylindrical body 100 The porous membrane part in which the circumferential surface was comprised with the porous membrane 101 The non-porous membrane part in which the circumferential surface was comprised with the other member 12 Inlet 14 Outlet 16 In the inside Wall surface 20 Introducing pipe 22 Member 30 Discharge pipe 32 Member 40 Storage part 42 Liquid b introducing pipe 44 Member 80 Seal ring

Claims (6)

A swirling flow generating step of flowing a swirling flow of the liquid a containing the reaction substrate A into a cylindrical body in which a part or all of the circumferential surface is formed of a porous membrane, and the reaction substrate A through the porous membrane Including a reaction step of supplying and mixing the liquid b containing the reaction substrate B capable of reacting with the swirl flow and reacting the reaction substrates A and B to precipitate crystal fine particles.
A method for producing crystalline fine particles. The cylindrical body has an inlet for the liquid a on a circumferential surface near one end, and an introduction pipe extending from the inlet substantially perpendicular to the axis of the cylindrical body and extending in a tangential direction of the cylindrical body. ,
The swirl flow generating step uses the introduction pipe to flow swirl flow by flowing the liquid a from the tangential direction of the inner wall surface of the cylindrical body that is substantially perpendicular to the axis of the cylindrical body. The manufacturing method of Claim 1 which is the process of flowing.   The manufacturing method of Claim 1 or 2 whose average particle diameter of the crystal microparticles | fine-particles in the said reaction process is 0.5-5 micrometers. A span of 0.5 to 1.5, wherein the crystalline fine particles are defined by the following formula (1):
Span = (d ₉₀ −d ₁₀ ) / d ₅₀ (1)
d ₁₀ : Particle diameter in 10% cumulative particle distribution d ₉₀ : Particle diameter in 90% cumulative particle distribution d ₅₀ : Production method according to claim 3, having a particle diameter in 50% cumulative particle distribution.   The manufacturing method according to any one of claims 1 to 4, wherein a ratio of a flow rate of the liquid a and a flow rate of the liquid b (flow rate of the liquid a / flow rate of the liquid b) is 4 to 10. (1) A cylindrical body in which part or all of the circumferential surface is composed of a porous membrane, and the inlet of the liquid a containing the reaction substrate A on the circumferential surface near one end and the other end A cylinder with a product outlet in the cross section,
The liquid a is connected to the inflow port so as to be able to flow in substantially perpendicular to the axis of the cylindrical body and from the tangential direction of the inner wall surface, and extends substantially perpendicular to the axis of the cylindrical body and in the tangential direction of the cylindrical body. Introduction pipe,
A storage part for storing the liquid b containing the reaction substrate B provided outside the circumferential surface of the cylindrical body, and a supply means for supplying the liquid b from the storage part into the cylindrical body;
Further comprising the step of preparing an apparatus comprising:
(2) The swirl flow generation step is a step of introducing the liquid a from the introduction pipe into the cylindrical body to generate a swirl flow,
(3) The reaction step is a step in which the liquid b is supplied to the swirl flow through the porous membrane and mixed, and the reaction substrates A and B are reacted to precipitate crystal fine particles. ,
The manufacturing method according to claim 1.